System and method for determining the origin of a sensed beat

Abstract

A method for monitoring a biological cardiac pacemaker is provided. The method may include stimulating a heart at a region selected for implantation of a biological pacemaker and sensing at least one electrical signal indicative of a cardiac depolarization originating in the region selected for implantation of the biological pacemaker. The method may further include sensing at least one subsequent electrical signal produced by the heart and determining if the subsequent electrical signal originated in the region selected for the biological pacemaker or another region of the heart. In an alternative embodiment, the method may include determining a template time difference between two points on cardiac complexes sensed in two or more different cardiac locations during normal sinus rhythm. The method may further include determining a time difference between two points on a subsequent cardiac complex sensed in two or more different cardiac locations. The time differences may be compared to determine if the subsequently-sensed cardiac complex originates in a left ventricular biological pacemaker site or in another cardiac site.

The invention claimed is: 
     
       1. A method for monitoring a biological cardiac pacemaker, comprising: stimulating a heart at a region selected for implantation of a biological pacemaker; sensing at least one electrical signal indicative of a cardiac depolarization originating in the region selected for implantation of the biological pacemaker; sensing at least one subsequent cardiac complex produced by the heart; and determining if the subsequent cardiac complex originated in the region selected for the biological pacemaker or another region of the heart. 
     
     
       2. The method of  claim 1 , wherein determining if the subsequently-sensed cardiac complex originated in the region selected for implantation of a biological pacemaker includes: determining a template waveform representative of a cardiac depolarization originating at the region selected for implantation of the biological pacemaker; and comparing the subsequently-sensed cardiac complex produced by the heart with the template waveform. 
     
     
       3. The method of  claim 2 , wherein comparing the electrical signal produced by the heart with the template waveform includes: selecting a first predetermined feature of the template waveform; selecting a predetermined feature of a subsequently-sensed cardiac complex; aligning the predetermined feature of the template waveform with the predetermined waveform of the subsequently-sensed cardiac complex; comparing the template waveform to the subsequently-sensed cardiac complex; and determining if the subsequently-sensed cardiac complex originated in the region selected for the biological pacemaker. 
     
     
       4. The method of  claim 1 , wherein determining if the subsequently-sensed cardiac complex originated in the region selected for the biological pacemaker or another region of the heart includes: determining a template cardiac vector from the cardiac complex originating in the region selected for implantation of the biological pacemaker; and determining a subsequent cardiac vector from the at least one subsequent cardiac complex produced by the heart. 
     
     
       5. The method of  claim 4 , further including comparing the template cardiac vector to the at least one subsequent cardiac vector. 
     
     
       6. The method of  claim 5 , wherein comparing the template cardiac vector to the at least one subsequent cardiac vector includes: determining a region surrounding the template cardiac vector; and determining if the subsequent cardiac vector is within the region surrounding the template cardiac vector. 
     
     
       7. The method of  claim 4 , wherein the template cardiac vector comprises two or more scalar values representing repeatably identifiable features of sensed cardiac signals. 
     
     
       8. The method of  claim 7 , wherein the repeatably identifiable features include at least one of a beginning of a cardiac depolarization, an end of a cardiac depolarization, a slew rate, a slope, and a maximum deflection. 
     
     
       9. The method of  claim 7 , wherein the repeatably identifiable features include at least one cardiac interval. 
     
     
       10. The method of  claim 9 , wherein the interval includes a time interval between a point within a cardiac signal sensed in a first cardiac channel and a point within a cardiac signal sensed in a second cardiac channel. 
     
     
       11. The method of  claim 9 , wherein the interval includes a time interval between two points within a cardiac signal sensed in a single cardiac channel. 
     
     
       12. The method of  claim 1 , wherein determining if the subsequent cardiac complex originated in the region selected for the biological pacemaker or another region of the heart comprises: determining a template morphology for a cardiac complex originating in a cardiac region corresponding to the region selected for the biological pacemaker; comparing a morphology of the cardiac complex in the first cardiac signal to a first template morphology and comparing the morphology of the cardiac complex in the second cardiac signal to a second template morphology; and classifying the cardiac complex as either originating in a biological pacemaker or another cardiac location based on the comparison of the morphology of the cardiac complex in the first cardiac signal and the second cardiac signal to the first template morphology and the second template morphology. 
     
     
       13. The method of  claim 1 , wherein determining if the subsequent cardiac complex originated in the region selected for the biological pacemaker or another region of the heart comprises: monitoring a first signal and a second signal representative of cardiac electrical activity; detecting a NSR cardiac complex in each of the first signal and the second signal; detecting at least one additional cardiac complex in each of the first signal and the second signal; locating a predetermined feature in the cardiac complex detected in the first signal and a first NSR representative complex, wherein the predetermined feature includes a repeatably identifiable complex section common to the cardiac complex detected in the first signal and the first NSR representative complex; aligning the predetermined feature in the at least one additional cardiac complex detected in the first signal and the first NSR representative complex; comparing the at least one additional cardiac complex detected in the second signal to a second NSR representative complex; and classifying the cardiac complex as a ventricular biologic pacemaker complex based on the comparison of the morphology of the cardiac complex in the second cardiac signal to the second NSR representative complex.